The present invention relates to a system for storing product containers.
US publication U.S. Pat. No. 5,370,492 discloses a storage system comprising a plurality of parallel racks, each rack comprising superimposed rows of side-by-side storage positions for product containers, as well as a guide system comprising horizontal longitudinal guides extending between rows of adjacent racks and horizontal transverse guides extending in transverse direction, transversely to the longitudinal guides. Trolleys can move from one longitudinal guide to another longitudinal guide within a layer of rows via a transverse guide, so that each trolley can be efficiently deployed for exchanging product containers with storage positions, irrespective of the row of which a respective storage positions forms part. Inevitably, there will be junctions, either crossings or T-junctions, between the longitudinal guides and the transverse guides, where a trolley can change its direction of movement at right angles without this causing a change in the orientation of the trolley. Each trolley is for that purpose provided both with longitudinal running wheels and with transverse running wheels. The vertical adjustment means enable the trolley either to have the longitudinal running wheels make contact with the longitudinal guides, in which case the transverse running wheels will be clear of the transverse guides, or to have the transverse running wheels make contact with the transverse guides, in which case the longitudinal running wheels will be clear of the longitudinal guides. The longitudinal guides comprise two opposite parallel longitudinal guide members and the transverse guides comprise two opposite parallel transverse guide members. The two longitudinal guide members of the longitudinal guides comprise C-shaped sections, with the open sides of the C-shape of respective longitudinal guide members forming a pair facing each other. The longitudinal running surface is formed by the lower horizontal leg of the C-shape. Each trolley is provided with eight longitudinal running wheels and eight transverse running wheels. Apart from the fact that this adds to the complexity and cost of the trolleys, the relatively large number of longitudinal running wheels and transverse running wheels has the drawback that vibrations will more easily occur in the trolley, so that there will be an increased risk of a product container falling off the trolley. Furthermore, the vibrations lead to undesirable noise and an additional mechanical load, and thus to wear on the trolleys. Within the framework of the ongoing effort to realise a more efficient use of a system as described in the introductory paragraph, there is a constant demand for faster-moving cars, which increases the above-described problem. Furthermore it is desirable that the installation height of the guide system is small so as to be able to utilize the overall height of the system in an efficient manner, and in addition it is desirable for the system to be constructionally simple, so that the cost price will remain within bounds, and in addition the configuration of the guide system preferably makes it possible to use a relatively simple embodiment of the trolleys that are used. Furthermore, the system must be safe in use, which implies, among other things, that derailing of the trolleys must be prevented. The above wishes and requirements are in many cases contradictory.
The object of the present invention is to provide the system as described in the introductory paragraph which, whether or not in preferred embodiments thereof, meets the various requirements mentioned in the foregoing. In order to achieve that object, a system according to claim 1 is provided. The significant advantage obtained with the system according to the invention is that the maximum height of the trolley in the transverse position thereof can remain within bounds. Thanks to this advantage the total height of the system is reduced, without this being realised at the expense of the other requirements as mentioned above. More specifically, the total height of the trolley in question in the transverse position thereof only needs to be slightly higher than the total height of the trolley in question in the longitudinal position, and in any case less higher than the height of the transverse guide members or at least than the highest of the transverse guide members and a longitudinal guide members.